Small volume pump



SMALL VOLUME PUMP Filed June 28, 1966 FIG. 2.

INVENTORS P.D. CHASTANG R. W. CHIDGEY AGENT United States Patent 3,382,811 SMALL VOLUME PUMP Pelham D. Chastang and Ronald W. Chitlgey, Pensacola, Fla, assignors to Monsanto Company, St. Louis, Mo., a corporation of Delaware Filed June 28, 1966, Set. No. 561,268 6 Claims. (till. 103-152) This invention relates to pumps, and more particularly, relates to a pump adapted to provide one or more continuous small volume liquid streams of uniform flow.

In many manufacturing operations there is a need for metering a plurality of liquid streams to a processing zone. in textile manufacturing, for example, filaments and yarns are customarily coated with liquid lubricants, finishes, or the like, and it is necessary to deliver one or more continuous metered streams of such liquids to the yarn finishing or coating areas. The use of conventional pumps, as gear pumps, for metering liquids to the yarns is not acceptable because fluctuations appear in the liquid streams. Fluctuations or pulses in a metered liquid stream i results in unequal amounts of liquid being deposited upon the yarns which in turn produces an uneven acceptance of dye in later yarn processing.

it is an object of this invention to provide a pump adapted to provide a micro-volume stream of liquid of uniform flow.

Another object of the invention is to provide a positive displacement pump having a plurality of variable volume chambers cycled in alternate and overlapping sequence to displace a constant supply of liquid into a mainstream.

Another object of the invention is to provide a pump simple in structure and inexpensive to produce.

According to the invention, the novel pump in a single unit structure comprises a pair of defined fluid pressure chambers and valve means for charging and venting each of the pair of fluid pressure chambers in alternate sequence. A pair of liquid inlet lines and a pair of liquid discharge lines are arranged to pass in mixed pairs through each of the defined fluid pressure chambers. The inlet lines are open at one end thereof to a source of supply of liquid and the pair of discharge lines are open at one end thereof to a main discharge line. In each portion of the inlet and discharge lines passing through the fluid pressure chambers there is interposed a resilient check valve. The other ends of the pairs of inlet and discharge lines are connected and open to a liquid displacement means adapted to receive liquid from the pair of inlet lines and to displace liquid into the discharge lines in alternate and overlapping cycle operation. A timing means is provided for controlling the actuation of the valve means so as to alternate the charging and venting sequence of the fluid pressure chambers during the overlapping cycle operation of the liquid displacement means.

In operation the liquid displacement means delivers liquid in alternate displacements to the main discharge line to form a mainstream of liquid of uniform flow.

A better understanding of the novel pump will be gained by reference to the following more detailed description and to the accompanying drawings.

In the drawings,

FIGURE 1 is an elevation view of the novel pump, and

FIGURE 2 is a perspective view of a multiple unit construction of the pump.

In the drawing, FIG. 1 illustrates a single unit construction and FIG. 2 a multiple unit construction of Lhe novel pump. Referring to FIG. 1, the basic components of the pump comprise a fluid pressure control unit 2 and a liquid displacement unit 4 with associated liquid inlet and discharge lines.

3,382,81 l Patented May 14, 1%68 The fluid pressure control unit 2 includes a casing 6 with a pair of fluid pressure chambers 8 and 10 defined therein. Each fluid pressure chamber 8 and 10 is in communication through lines 12 and 14, respectively, with a timed fluid pressure valve 16 of conventional solenoid type. Fluid pressure valve 16 is timed to maintain a charged condition in one chamber 8 while maintaining a vented condition in the other chamber 10, and then to reverse the conditions of the chambers so that chamber 10 is charged with air under pressure while chamber 8 is vented, as will be explained in more detail hereafter.

The liquid displacement unit 4 comprises a pair of bellows 18 and 20, each of which defines an expansible variable chamber 22 and 24, respectively. Each chamber 22 and 24 is open to an inlet line 26 and 28, respectively, in turn open to a source of liquid, and the chambers are also open to a corresponding discharge line 39 and 32, respectively, for displacing liquid thereto. The inlet and discharge lines 26, 28, 30 and 32 each pass sealingly through fluid pressure chambers 8 and 10 in mixed relation. That is, inlet line 26 connected to bellows 13 passes through chamber 1% and inlet line 28 connected to hellows 29 passes through chamber 8, whereas, discharge line 30 connected to bellows 18 passes through chamber 8 and discharge line 32 connected to bellows 20 passes through chamber 10'. Discharge lines 30 and 32 leaving chambers 8 and 10 connect to a main discharge line 34, and inlet lines 26 and 28, preferably, connect to a main inlet line 36 but may connect to individual sources of liquid supply. Each inlet line is shown connected to a respective discharge line adjacent the bellows, but it will be understood tthat each inlet line can be connected directly to the bellows.

Interposed in a portion of each inlet and discharge line 26, 28, 3t? and 32 passing through chambers 8 and 10 is a resilient check valve 38, 4t 42, and 4-4, respectively, preferably of arcuate and tubular configuration.

The expansible bellows i8 and 2d are actuated to expand and contract by means of an eccentrically mounted driven cam 46 that engages the bottom of bellows 13, and by a pivoted lever 48 having rotatable follower rollers 5t} and 52 at each end thereof that engage cam 46 and the bottom of bellows 26, respectively. Bellows 18 and 20 are mounted fixedly so that they exert a force against cam 46 and roller 52, respectively.

Lever 48 is positioned so that follower roll 50 is mounted to contact cam 46 at a point from or opposite to the point of contact of cam 46 with bellows 18. Cam 46 is eccentrically mounted and shaped, accord ing to a workable embodiment, to provide repeated and alternate actuation of bellows 18' and 20 in the following sequences or cycles-a lift cycle for lifting the bellows 18 and 20 to contact the latter for 192 of cam 46 rotation, a dwell cycle for causing the bellows l8 and 20 to dwell in the lifted position for 72 of cam rotation, and a fall cycle for causing the bellows 18 and 20 to fall and expand for 96 of cam rotation. Cam 46, therefore, has lift, dwell, and fall sector (A, B, and C, respectively) that impart corresponding cyclical actuation to bellows it; and 26. Since bellows 13 and 20 are positioned in opposed 180 relation and since the lift or discharge sector of cam 46 is 192 of rotation, there is an overlap period of 12 of cam rotation when both bellows 18 and 2d are being lifted and thus contracted to eifect a discharge of liquid. This feature is important as will be explained later.

The fluid pressure valve 16 is synchronized to the mic.- tion of cam 46 so that valve 16 receives a signal to reverse the pressurizing and venting of chambers 8 and 10 during the 12 period of overlap cam and bellows operation. A conventional microswitch arrangement may be used. The synchronization is illustrated diagrammatically by 3 the broken line 54 and by a microswitch arrangement 55, shown in FIG. 2.

In operation, assume that liquid is supplied to supply line 36, that chamber 8 is vented, that chamber 10 is charged with air under pressure so that resilient valves 42 and 44 are compressed to a close-d position, that cam 46 is rotating in a clockwise direction and is in a position approximately midway through the lift or discharge sector in relation to bellows 18 and the fall sector is contacting roller 50 thereby actuating bellows 21) through a fall cycle, as shown in FIG. 1.

In the condition above, valve 40 is open and since bellows 20 is expanding due to the follower lever 48 being pivoted by cam 46 in a clockwise direction thereby moving follower roller 52 downwardly, variable chamber 24 of bellows 20 will be taking in liquid via inlet line 28. Resilient valve 44 is in a compressed, squeezed, or closed position there-by cutting off discharge line 32 from line 34. Meanwhile, inlet line 42 is compressed and closed, discharge line 38 is open and cam 46 is actuating bellows 18 through a lift cycle thereby contracting bellows i8 and causing liquid from expansible chamber 22 to be displaced into discharge line 34 via line 30 past resilient valve 38.

As cam 46 rotates clockwise, liquid is displaced from bellows 18 but flows into bellows 20 up to such a time when cam 46 rotates to a position where the lift sector A of cam 46 contacts roller 50 to cause lever 48 to pivot in a counter-clockwise direction moving follower roller 52 upwardly and causing bellows 20 to contract. Bellows 20 will begin to discharge liquid back through the inlet line 28 since the discharge line 32 is closed. At this time, bellows 18 is still being contracted by cam 46 and bellows l8 and 20 are thus in an overlap discharge cycle. A signal is now transmitted to the fluid pressure valve 16 and the latter acts responsively to vent fluid pressure chamber 10 and to pressurize fluid pressure chamber 8.

With chamber 8 pressurized, valves 38 and 40 are squeezed or compressed to check the flow of liquid through discharge line 38 and to shut-01f the flow of liquid to bellows 20. Chamber 10' being vented, valves 42 and 44 will return flexibly to the normal open position to permit liquid to flow to bellows l8 and to open the discharge line 32 to the main discharge line 34. The arcuate configuration of the resilient valves causes the valves to more readily close and open in response to external pressure. The degree of valve overlap is short and the changeover of liquid displacement from discharge line 30 to discharge line 32 is co-current and instantaneous.

When cam 46 rotates clockwise through 192 and the dwell sector B of cam 46 contacts bellows 18, the latter is not actuated but lever 48 continues to be pivoted in a counterclockwise direction causing bellows 20 to contract and to displace liquid therefrom into the main discharge line 34 via open resilient valve 44.

After cam 46 has rotated through the lift A and dwell B sectors relative to bellows 13, the fall sector C contacts bellows 18 and effects an expansion thereof whereby liquid flows thereto through valve 42. Liquid will continue to flow to bellows 18 for 96 of cam 46 rotation while liquid is being discharged from bellows 20. Then, the cam lift sector A once again contacts bellows 18 while 12 of cam lift sector A still remains to contact roller 50. Bellows 18 and 20 are now in the overlap lift or discharge cycle again and, as before, a signal is sent to fluid pressure valve 16. Responsively thereto, valve 16 is actuated to reverse the pressurizing and venting of chambers 8 and 10 so that chamber 8 is vented and chamber 10 is charged with air under pressure. The effect will be the same as described before except the procedure is reversed so that liquid is now displaced from bellows 18 into main discharge line 34 while bellows 20 is actuated correspondingly according to the configuration of the dwell B and fall C sectors of cam 46.

The 12 overlap in cycle operation, when both bellows are discharging, is important to overcome problems of non-uniform flow during the changeover of liquid discharge from one bellows to the other. Uniformity in flow is obtained because each bellows preceding discharge into the main discharge line is primed and discharging a uniform flow of liquid back through the inlet line. A quick and rapid reversal of chamber 8 and it venting and pressurization by valve 16 during the 12 overlap dis charge period provides a ready and uninterrupted uniform delivery of liquid to the main discharge line 34 resulting in a uniform mainstream flow of liquid.

The single discharge stream structure of FIG. l is readily mo-difyable as shown in FIG. 2 to provide a plurality of streams. Components in FIG. 2 which are similar to those of FIG. 1 are designated by like reference numerals. A plurality of liquid displacement units 4 are provided and all of the lines 26, 28, 30 and 32 are arranged to pass through chambers 8 and 10. The cams 46 are driven through a common shaft. The multiple unit of FIG. 2 operates similarly to the single unit of PEG. 1.

It will be understood that variations and modifications are contemplated within the spirit of the invention and that the invention be limited only by the following claims.

We claim:

1. A pump comprising,

a pair of defined fluid pressure chambers,

valve means for charging and venting each of said pair of fluid pressure chambers in alternate sequence,

a pair of liquid inlet lines and a pair of liquid discharge lines arranged to pass in pairs through said pair of defined fluid pressure chambers, said pair of inlet lines being open at one end thereof to a source of supply of liquid and said pair of discharge lines being open at one end thereof to a main discharge line,

resilient valve means interposed in each of the portions of said inlet and said discharge lines passing through said pair of fluid pressure chambers,

liquid displacement means, open to the other ends of said pairs of inlet and discharge lines, adapted to receive liquid from said pair of inlet lines and to displace liquid into said pair of discharge lines in alternate and overlapping cycle operation.

timing means for controlling the actuation of said valve means to alternate the charging and venting sequence of said fluid pressure chambers.

2. A pump as in claim 1, wherein said pair of liquid inlet lines and pair of liquid discharge lines are arranged to pass through said pair of defined fluid pressure chambers in mixed pairs.

3. A pump comprising,

a plurality of defined fluid pressure chambers,

a plurality of liquid inlet lines and a plurality of liquid discharge lines passing in mixed relation through each of said plurality of fluid pressure chambers, said plurality of discharge lines being open at one end thereof to a plurality of main discharge lines and said inlet lines being open at one end thereof to a source of supply of liquid,

resilient valve means interposed in each of the portions of said inlet and discharge lines passing through said plurality of fluid pressure chambers,

liquid displacing means open to the other ends of said inlet and discharge lines for receiving liquid from said plurality of inlet lines and for displacing liquid into said plurality of discharge lines in alternate and overlapping cycle,

timed valve means for charging and venting each of said fluid pressure chambers in alternate chargingventing sequence with the sequence being change during the overlapping discharge cycle of the liquid displacing means for controlling said resilient valve means to provide a constant displacement of liquid from said liquid displacement means into said main discharge line.

4. A pump as in claim 3, wherein said resilient valve means comprises arcuate resilient tubing.

5. A pump as in claim 3, wherein said liquid displacement means comprises a plurality of expansible bellows and a. cam and follower assembly adapted to actuate said eXpansib-le bellows to displace liquid therefrom in alternate and overlapping cycle.

6. A pump comprising,

a pair of fluid pressure chambers,

valve means timed to charge and vent said pair of fluid pressure chambers in alternate sequence,

a pair of expansible bellows,

a driven cam and follower assembly for actuating said pair of expansible bellows through a lift, dwell, and fall cycle in continuous, alternate sequence with an overlap in the lift cycle,

an inlet line open at one end thereof to a source of liquid and a discharge line open at one end thereof to each of said expansible bellows, said inlet and discharge lines being arranged to pass through said fluid pressure chambers in mixed relation so that an inlet line associated With one expansible bellows and a discharge line associated with the other expansible bellows pass through a respective fluid pressure chamber,

resilient valve means interposed in each of the portions of said inlet and discharge lines passing through said pair of fluid pressure chambers,"

a main discharge line into which said discharge lines open,

said timed valve means being timed to reverse the charging-venting sequence of said pair of fluid pressure chambers during the overlap of the lift cycle of the expansible bellows to open and close said resilient valve means whereby the displaced liquid from each bellows is alternately displaced into said main discharge line to form one continuous uniform liquid mainstream.

References Cited UNITED STATES PATENTS 3,007,416 11/1961 Childs 103148 XR 3,020,846 2/1962 Thomas 103148 XR 3,148,624 9/1964 Baldwin 10'3148 XR 3,154,021 10/1964 Vick 103152 XR 3,175,498 3/1965 Rohrer 103-148 XR 3,250,226 5/1966 Voelker 103-152 DONLEY J. STOCKING, Primal Examiner.

25 T. R. HAMPSHIRE, Assistant Examiner. 

6. A PUMP COMPRISING, A PAIR OF FLUID PRESSURE CHAMBERS, VALVE MEANS TIMED TO CHARGE AND VENT SAID PAIR OF FLUID PRESSURE CHAMBERS IN ALTERNATE SEQUENCE, A PAIR OF EXPANSIBLE BELLOWS, A DRIVEN CAM AND FOLLOWER ASSEMBLY FOR ACTUATING SAID PAIR OF EXPANSIBLE BELLOWS THROUGH A LIFT, DWELL, AND FALL CYCLE IN CONTINUOUS, ALTERNATE SEQUENCE WITH AN OVERLAP IN THE LIFT CYCLE, AN INLET LINE OPEN AT ONE END THEREOF TO A SOURCE OF LIQUID AND A DISCHARGE LINE OPEN AT ONE END THEREOF TO EACH OF SAID EXPANSIBLE BELLOWS, SAID INLET AND DISCHARGE LINES BEING ARRANGED TO PASS THROUGH SAID FLUID PRESSURE CHAMBERS IN MIXED RELATION SO THAT AN INLET INLET ASSOCIATED WITH ONE EXPANSIBLE BELLOWS AND A DISCHARGE LINE ASSOCIATED WITH THE OTHER EXPANSIBLE BELLOWS PASS THROUGH A RESPECTIVE FLUID PRESSURE CHAMBER, RESILIENT VALVE MEANS INTERPOSED IN EACH OF THE PORTIONS OF SAID INLET AND DISCHARGE LINES PASSING THROUGH SAID PAIR OF FLUID PRESSURE CHAMBERS, A MAIN DISCHARGE LINE INTO WHICH SAID DISCHARGE LINES OPEN, SAID TIMED VALVE MEANS BEING TIMED TO REVERSE THE CHARGING-VENTING SEQUENCE OF SAID PAIR OF FLUID PRESSURE CHAMBERS DURING THE OVERLAP OF THE LIFT CYCLE OF THE EXPANSIBLE BELLOWS TO OPEN AND CLOSE SAID RESILIENT VALVE MEANS WHEREBY THE DISPLACED LIQUID FROM EACH BELLOWS IS ALTERNATELY DISPLACED INTO SAID MAIN DISCHARGE LINE TO FORM ONE CONTINUOUS UNIFORM LIQUID MAINSTREAM. 